1. Field of the Invention
This invention relates to apparatus for heat-treating pharmaceuticals. More particularly, this invention relates to apparatus for heat-treating mannitol in order to prevent recrystalization of dissolved solid material in a mannitol solution.
2. Statement of Problem and Prior Art Solutions
Mannitol is a widely used diuretic that is injected intraveneously during operations in order to cause patients being operated upon to promptly urinate during the operation so that injurious substances can be passed from the body or so that a urinalysis can be performed while the patient is still on the operating table.
Mannitol tends to recrystalize when stored for any length of time and cannot be injected if crystals are present. In accordance with the usual approach, these crystals are dissolved by either heating the mannitol in a hot water bath or an autoclave while still in the vial or ampule. In accordance with the directions for dissolving crystals in "MANNITOL, MSD" manufactured by the Merick, Sharp & Dohme Company and sold in ampules, crystals are removed by heating a water bath to 80.degree. C., removing the water bath from its heat source and then immersing the ampule of mannitol for fifteen to twenty minutes. In an alternative approach, the ampules of mannitol are autoclaved for twenty minutes at 120.degree. C. (fifteen PSI). As soon as the ampules are cool enough to handle, they are shaken gently and allowed to cool to body temperature before use. The mannitol injection sold by "invenex" is packed in a vial and requires heating to 100.degree. C. or autoclaving for twenty minutes at 120.degree. C. in order to dissolve crystals. The vial containing the mannitol must then be shaken several times as the temperature drops and cooled to body temperature before injecting.
As is readily seen, providing dissolved mannitol on an ongoing basis can be a tedious process. Frequently, all of the mannitol available in a hospital pharmacy is crystalized and must be heat-treated before use. During an operation, the mannitol is needed immediately and the delay necessitated by heat-treating can adversely affect an operation. Even if a program is established for heat-treating mannitol on an ongoing basis, it can be both expensive and inconvenient if the directions supplied with mannitol dosages are complied with. Certainly, boiling water and then immersing mannitol vials in the water is a tedious approach while autoclaving the vial is also a tedious and perhaps expensive approach. An empty autoclave may not be available and in order to ensure that there is always an autoclave available for mannitol, an additional autoclave is sometimes provided at considerable expense. In any event, providing a ready supply of crystal free mannitol is, to say the least, an irritating administrative problem.
The existence of this problem has been long recognized and attempts to redissolve mannitol crystals by using microwave ovens have been suggested. However, there has been one instance of a mannitol vial exploding while in a microwave oven causing considerable damage to the oven and endangering personnel nearby. It has also been suggested to keep mannitol in warming cabinets so that a ready supply of mannitol is available for immediate use. However, warming cabinets are expensive and are not necessarily appropriate dissolving existing crystals. Moreover, warming cabinets are not designed to take the abuse which often occurs in a busy hospital pharmacy in which vials may from time-to-time be broken and spilled within the cabinets. Accordingly, warming cabinets are not widely used to prevent recrystalization of mannitol.
Clearly, there is a need for an alternative cost effective approach which will encourage hospital pharmacies to always have a ready supply of dissolved mannitol available.